@lradden have you tried contacting the previous webmaster? Looks like it’s missing a plugin like Courseware perhaps, sound familiar or one of the learning management systems. Check in your Plugins > Installed panel. The lessons plugin may have been deactivated.

Otherwise, where are you hosted? If on shared host, perhaps tech support can get you a copy of your database backup from last month at least to check wp_options table to see what were the active plugins at that time.